15 of 16 people found the following review helpful
5.0 out of 5 stars
Fantastic Book, May 5 2008
By Bill MacLean - Published on Amazon.com
This review is from: Information Modeling and Relational Databases (Hardcover)
Everyone needs this book. Read more to find out why:
If you intend to create genuinely useful business applications without first creating an accurate conceptual data model and deriving the database schema from the model, then I hope your projects have very large budgets and flexible deadlines, because you'll need both. Accurate conceptual data models are not an academic curiousity, they are a practical necessity. Well designed databases are the heart of every business application, and accurate conceptual data models are the foundation of every well designed database.
This book presents a method for data modeling called Object Role Modeling (ORM). If you've never created a data model before, you might as well learn the best method from the start. If you've used E-R (Entity Relationship) modeling before, this is your chance to learn a method that overcomes the limitations of E-R, while building on the knowledge you already have.
ORM is based on facts (assertions about the business sphere you are modeling), not entities and attributes. Business users understand facts much better than they understand data modeling abstractions. By using ORM facts, you create your data model in a language that business users can understand and validate. Poor communication with business users and inadequate understanding of requirements are major causes of design deficiencies. ORM solves these issues through its fact based approach.
ORM is also much more expressive than any other popular data modeling notation, ncluding UML and all major flavors of E-R. Many business rules should be expressed as data constraints, but traditional data modeling languages don't do well at capturing these constraints. By capturing the constraints in an ORM model and validating with the users, you make the construction of a good application much easier.
Halpin is an excellent writer, and this book is very easy to read. The many examples and crisp writing style mean that you'll actually understand what the author intends, a refreshing change from most computer books. If you've read the previous edition of this book, this update is very worthwhile. There is a lot of expanded and new material, and you'll be happy you purchased the new edition.
8 of 8 people found the following review helpful
5.0 out of 5 stars
The best book on database design, April 17 2008
By Andrew Carver - Published on Amazon.com
This review is from: Information Modeling and Relational Databases (Hardcover)
This new edition of Information Modeling and Relational Databases maintains its predecessor's achievement of being the best, most complete book out there on design of information systems, and particularly of database schemas -- and of seeming a few decades ahead of the rest of the pack! The relational database theory world seems to move at a rather glacier-like pace -- with the result that some of the schema design methods still in common use have stayed well past their "obsolete by" date. But as a reviewer of the first edition said, this book presents MATURE database design technology; and it can only be hoped that the database design world will sooner, rather than later, realize the immense, and immensely practical, value of the mature theory and design procedure that this book presents. Do you want to be able to arrive at the correct schema the first time? or even to know whether you've reached it or not? This is the book that shows you how, and gives you a rich, formal modeling notation that has very significant and improving tool support. Terry and Tony have both added very valuable new chapters to the book, and expanded and updated the other chapters, so that this is a very much improved book -- as amazing as that may seem to those (like me) who loved the first edition. This book will, in my opinion, be setting the standard for books on information system design for many years to come.
3 of 3 people found the following review helpful
5.0 out of 5 stars
Get to a higher level when modeling data: concept models, Sep 11 2009
By Henry Carvajal - Published on Amazon.com
This review is from: Information Modeling and Relational Databases (Hardcover)
Before knowing about Dr. Helpin's CSDP, I often struggled to find the appropiate data model for the project at hand. Model validation with users was not straight-forward: users do not think of the world in terms of entities and relationships of the ER model - They think about facts and concepts. Now, I do not try to fight with a data model, I build the ORM model and let the procedure to build the ER one.